iOS总结小知识（二）

1、UITextView中打开或禁用复制、剪切、选择、全选等功能：
//继承UITextView重写这个方法

-(BOOL)canPerformAction:(SEL)action withSender:(id)sender
{
 //返回NO为禁用，YES为开启
 //粘贴
 if(action == @selector(paste:)) return NO;
 //剪切
 if(action == @selector(cut:)) return NO;
 //复制
 if(action == @selector(copy:)) return NO;
 //选择
 if(action == @selector(select:)) return NO;
 //选中全部
 if(action == @selector(selectAll:)) return NO;
 //删除
 if(action == @selector(delete:)) return NO;
 //分享
 if(action == @selector(share)) return NO;
 return [super canPerformAction:action withSender:sender];
}

2、为一个View添加虚线边框

 CAShapeLayer * border = [CAShapeLayer layer];
 border.strokeColor = [UIColor colorWithRed:67/255.0f green:37/255.0f
blue:83/255.0f alpha:1].CGColor;
 border.fillColor = nil;
 border.lineDashPattern = @[@4,@2];
 border.path = [UIBezierPath bezierPathWithRect:view.bounds].CGPath;
 border.frame = view.bounds;
 [view.layer addSublayer:border];

3、修改cell.imageView的大小

 UIImage * icon = [UIImage imageNamed:@""];
 CGSize itemSize = CGSizeMake(30,30);
 UIGraphicsBeginImageContextWithOptions(itemSize,NO,0.0);
 CGRect imageRect = CGRectMake(0.0,0.0,itemSize.width,itemSize.height);
 [icon drawInRect:imageRect];
 cell.imageView.image = UIGraphicsGetImageFromCurrentImageContext();
 UIGraphicsEndImageContext();

4、在指定的宽度下，让UILabel自动设置最佳font

 label.adjustsFontSizeToFitWith = YES;

5、在状态栏增加网络请求的菊花，类似safari加载网页的时候状态栏菊花

 [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

6、tableViewCell分割线顶到头

-(void)tableView:(UITableView *)tableView willDisplayerCell:(UITableViewCell *)cell
forRowAtIndexPath:(NSIndexPath *)indexPath
{
 [cell setSeparatorInset:UIEdgeInsetsZero];
 [cell setLayoutMargins:UIEdgeInsetsZero];
 cell.preservesSuperviewLayoutMargins = NO;
}
- (void)viewDidLayoutSubviews{
 [self.tableView setSepatatorInset:UIEdgeInsetsZero];
 [self.tableView setLayoutMargins:UIEdgeInsetsZero];
}

7、设置tableView分割线颜色

 [self.tableView setSeparatorColor:[UIColor myColor]];

8、设置屏幕方向

 [[UIDevice currentDevice] setValue:@(UIInterfaceOrientationLandscapeLeft)
forKey:@"orientation"];

9、在非ViewController的地方弹出UIAlertController对话框

 //最好抽成一个分类
 UIAlertController * alertController = [UIAlertController
alertControllerWithTitle:@"Title" message:@"message"
preferredStyle:UIAlertControllerStyleAlert];
 id rootViewController = [UIApplication
sharedApplication].delegate.window.rootViewController;
        if([rootViewController isKindOfClass:[UINavigationController class]])
 {
 rootViewController = ((UINavigationController
*)rootViewController).viewController.firstObject;
 }
 if([rootViewController isKindOfClass:[UITabBarController class]])
 {
 rootViewController = ((UITabBarController
*)rootViewController).selectedViewController;
 }
 [rootViewController presentViewController:alertController animated:YES
completetion:nil];

10、禁用系统滑动返回功能

-(void)viewDidAppear:(BOOL)animated
{
 [super viewDidAppear:animated];
 if([self.navigationController respondsToSelector:@selector
(interactivePopGestureRecognizer)]){
 self.navigationController.interactivePopGestureRecognizer.delegate = self;
 }
}
-(void)viewWillDisappear:(BOOL)animated{
 [super viewWillDisappear:animated];
 if([self.navigationController respondsToSelector:@selector
(interactivePopGestureRecognizer)]){
 self.navigationController.interactivePopGestureRecognizer.delegate = nil;
 }
}
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer*)gestureRecognizer
{
 return NO;
}

11、合并两个图片

+ (UIImage*)mergeImage:(UIImage*)firstImage withImage:(UIImage*)secondImage {
    CGImageRef firstImageRef = firstImage.CGImage;
    CGFloat firstWidth = CGImageGetWidth(firstImageRef);
    CGFloat firstHeight = CGImageGetHeight(firstImageRef);
    CGImageRef secondImageRef = secondImage.CGImage;
    CGFloat secondWidth = CGImageGetWidth(secondImageRef);
    CGFloat secondHeight = CGImageGetHeight(secondImageRef);
    CGSize mergedSize = CGSizeMake(MAX(firstWidth, secondWidth), MAX(firstHeight,
secondHeight));
    UIGraphicsBeginImageContext(mergedSize);
    [firstImage drawInRect:CGRectMake(0, 0, firstWidth, firstHeight)];
    [secondImage drawInRect:CGRectMake(0, 0, secondWidth, secondHeight)];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

12、AFNetworking监听网络状态

// 监听网络状况
    AFNetworkReachabilityManager *mgr = [AFNetworkReachabilityManager sharedManager];
    [mgr setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {
        switch (status) {
            case AFNetworkReachabilityStatusUnknown:
                break;
            case AFNetworkReachabilityStatusNotReachable: {
                [SVProgressHUD showInfoWithStatus:@"当前设备无网络"];
            }
                break;
            case AFNetworkReachabilityStatusReachableViaWiFi:
                [SVProgressHUD showInfoWithStatus:@"当前Wi-Fi网络"];
                break;
            case AFNetworkReachabilityStatusReachableViaWWAN:
                [SVProgressHUD showInfoWithStatus:@"当前蜂窝移动网络"];
                break;
            default:
                break;
        }
    }];
    [mgr startMonitoring];

13、获取设备mac地址

+ (NSString *)macAddress {
    int                 mib[6];
    size_t              len;
    char                *buf;
    unsigned char       *ptr;
    struct if_msghdr    *ifm;
    struct sockaddr_dl  *sdl;
 
    mib[0] = CTL_NET;
    mib[1] = AF_ROUTE;
    mib[2] = 0;
    mib[3] = AF_LINK;
    mib[4] = NET_RT_IFLIST;
 
    if((mib[5] = if_nametoindex("en0")) == 0) {
        printf("Error: if_nametoindex error\n");
        return NULL;
    }
 
    if(sysctl(mib, 6, NULL, &len, NULL, 0) < 0) {
        printf("Error: sysctl, take 1\n");
        return NULL;
    }
 
    if((buf = malloc(len)) == NULL) {
        printf("Could not allocate memory. Rrror!\n");
        return NULL;
    }
 
    if(sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
        printf("Error: sysctl, take 2");
        return NULL;
    }
 
    ifm = (struct if_msghdr *)buf;
    sdl = (struct sockaddr_dl *)(ifm + 1);
    ptr = (unsigned char *)LLADDR(sdl);
    NSString *outstring = [NSString stringWithFormat:@"X:X:X:X:X:X",
                           *ptr, *(ptr+1), *(ptr+2), *(ptr+3), *(ptr+4), *(ptr+5)];
    free(buf);
 
    return outstring;
}